The creation of the lake reservoirs

The creation of the lakes – Why the Grands Lacs de Seine ?

Lac d’Orient – also called " Seine Reservoir"

Projects to control the Seine basin were made following the important floods at the start of the C20th (1910, 1924) and the drought in 1921. The aim was to reduce the catastrophic damage caused by the floods in the Paris basin linked to the episodic renewal of such phenomena . The works were also expected to maintain the water level in Summer and Autumn in the river that fed the capital and ensured navigation to the sea.

The Chabal Project.

Chabal, an engineer, presented a comprehensive project concerning the river and it's main tributaries : Yonne, Aube, and Marne. Barrages would allow the accumulation of water in Winter so it could be released in Summer. The decision was taken after the floods in 1924.The first works were constructed on the Armançon, Cure and Yonne. Then the barrage at Champaubert-aux- Bois was put into service in 1938. The lake reservoir Marne reached a capacity of 350 million cubic metres.

The Declaration of Public Utility was taken on 25th May 1959 during an Interministerial Council presided over by Monsieur Michel DEBRE. The work of re-establishing communications was started at the beginning of 1960. It required the construction of 26 road bridges, 2 footbridges and 10 km of new roads. As part of the development of tourism, a 25 km tourist route was made at the lake's edge. A 12.5 km, intake partly underground, conducted the waters of the Seine towards the lake reservoir. Five compacted silt dykes closed the natural basin that occupied a large natural depression. The highest was 24 m. Another canal, divided into 2 branches, with a total length of 24.5 km returned the water to the Seine in Summer and Autumn.

The works cover an area of about 2, 800 hectares : 1 ,500 hectares of wood, 900 hectares of land, meadows, pastures and parks, 160 hectares of ponds and pools, 200 hectares of fallow land and scrubland. It took seven years to build and up to 350 workers were employed.The masses of material moved were counted in tens of millions of m3. At the end of this impressive task, the Lac d’Orient covered an area of 2,300 hectares and had a storage capacity of 208 million m3. If was officially inaugarated on 9th March 1966 by Monsieur Edgar PISANI, Minister of Equipment, during it's first impoundment.

The impoundment of the lake reservoir Seine took place in 1966.

It occupies a large natural depression with clay soil, once wooded, dotted with ponds and almost uninhabited. However, the vegetation bordering the lake is directly dependent on the annual rhythm of emptying. The variation in the level of the lake contributes to it's floral richness. Remarkable species have been listed :small fleabane, grass-leaved water plantain, water mudwort, wood sage… The Lac d’Orient has become a Mecca for ornithology. Over more than twenty years, almost 260 species have come to the lakes particularly during the large migrations: cranes, ducks, wild geese, birds of prey. Rare species have been seen : black storks, ospreys. The ornithological interest is recognised at an international level ( RAMSAR Convention ), a European level (NATURA 2000) and a national level (Forêt d’Orient National Nature Reserve). Every ten years, the lake is emptied completely to undertake security checks , maintenance and improvements. The last time was in 2008. It allowed an assessment to be made.

The Lacs Temple and Amance reservoir Aube

1990 saw the impoundment of the reservoir Aube. The two basins complete the system of water regulation . They are fed by the river Aube, tributary of the Seine. The building of the reservoir took from 1981 to 1988. As the new lake reservoir was being situated in a Nature Park, it's insertion in the environment necessitated studies and special adaptations, under the direction notably of the Institution Interdépartementale des Barrages-Reservoirs.

Reservoirs of the Seine basin (IIBRBS).

There are two basins: Auzon-Temple (1,800 ha) and Amance (500 ha), linked by a canal.
The work was undertaken in several stages: water supply, intake,Amance basin with the Radonvilliers dyke , junction canal and Brevonnes dyke. Four hundred people including two hundred and sixty workers were employed for three years. An important fleet of vehicles was needed . Seven kilometres of roads had to be modified, as well as an SNCF bridge and17 km of EDF lines.

The Brevonnes dyke is very impressive. It was at the time of it's construction the largest earthmoving site in France:a dyke 10 km long with a maximum height of 22.5 m and a width of about 165m at the base. It required 7 millions cubic metres of hard core, silt and clay. Five ponds existed before the construction of the reservoir . (Rossignol, Le Marmoret, l’Oson , La Pierre et Frouasse. ) Three of them were restored, their dykes raised and solidified to maintain a constant level during their annual or ten-yearly drainage. Five reservoirs were also built in the headwaters so as to favour reproduction of the fish stocks. Valois,Grand Orient, Fontaine aux oiseaux, Frouasse et Pavillon Henri contain 14 million cubic metres of water. At the same time, the Park set up a programme for the rehabilitation of forest pools.

In 1998, a management plan for the Pelouse des Brebis was started (Site Natura 2000. Brienne-la-Vieille). Measuring 40 ha, it's one of the only alluvial grasslands on sand in the whole region.